Summary Three dimensional (3D) microphysiological systems (MPS) represent a powerful intermediate model system employing human cells and tissues capable of bridging in vitro studies and clinical trials. We propose to create an integrated MPS platform to more accurately model the complex cellular interactions involved in human type 1 diabetes (T1D) pathogenesis. We previously generated an MPS containing novel extracellular matrix hydrogels that support sustained islet function and T cell migration along the islet cell surface in 3D (CHIB), and in first-of-their-kind studies, we demonstrated antigen-specific IGRP-reactive human CD8 T cells resulted in targeted ?-cell killing (CMAI). Here, we propose an interdisciplinary effort to integrate and expand the MPS platform (referred to as the islet-immune Chip (iiChip)), as well as the cell-based technologies facilitating testing of antigen-specific T cells, isogenic cellular systems capable of deriving multiple cellular lineages, and genome editing technologies for use by the broader HIRN community. Specifically, we will utilize islets or islet- like spheroids, endothelial cell monolayers, and innate and adaptive immune cells, including dendritic cells (DCs), macrophages, CD4+ conventional T cells (Tconv), CD8+ cytotoxic T cells (CTLs), and regulatory T cells (Tregs), to model the spatial configuration and complex cellular interactions involved in human T1D pathogenesis. We hypothesize that this optimized 3D iiChip will facilitate in situ interrogation of Ag- specific and genotype-phenotype interactions that are essential in T1D pathogenesis as well as the mechanistic effects of immunomodulatory therapies with spatial and temporal control. Experimental deliverables will include the ability to assess islet:immune interactions utilizing real-time high-resolution imaging and quantitation of cellular interactions, trafficking, extravasation, and ?-cell function/survival. Key features of the iiChip will involve the integration of in-line sensors and bioreporters, spatial and temporal control of inputs for defined stimulation, and integration of matrices with the capacity for fluidic and cellular recirculation, measurement of soluble and cellular readouts in long-term cell culture. In addition, gene edited induced pluripotent stem cells (iPSC) from male and female donors with T1D-risk associated HLA will be available for the generation of immune, endothelial, and endocrine cells that are essential for building an isogenic ?disease-on-a-chip? model. When loaded with primary human cells or isogenic iPSC-derived materials (i.e., endothelial, immune, and ?-cells), this iiCHIP will enable dynamic interrogation of genotype-phenotype interactions, antigen-specific ?-cell killing, and effects of immunomodulatory therapies within a fluidic 3D microenvironment. The iiChip will enable mechanistic studies capable of expediting clinical interventions aimed at inhibition of immune-mediated ?-cell destruction, enhancing immune regulation, and testing of ?-cell restorative therapies.